Acyclische und cyclische Silylazine und Azinylsilane / Acyclic and Cyclic Silyalzines and Azinylsilanes

Abstract

C-lithiated bis(tert-butyl-methyl)ketazine reacts with halosilanes to give the monosilylketazines, t-Bu(Me)C=N-N=C(t-Bu)-CH2R, (1 - 7). (1: R = SiMe3; 2: R = SiClMe2; 3: R = SiClMePh; 4: R = Cl2SiPh; 5: R = SiCl3; 6: R = SiMe2Ph; 7: R = F2SiN(t-Bu)SiMe3). The bis(ketazinyl)silanes [t-Bu(RCH2) C = N-N = CCH2-t-Bu]2 SiMe2 8, 9 are formed in the reaction of the same lithiated ketazine or 1 with Cl2SiMe2 in a molar ratio of 2 : 1, (8: R = H; 9: R = SiMe3). Di(silyl)ketazines (10, 11) are obtained from lithiated 1 and ClSiMe2Ph in a molar ratio of 1:1 and from dilithiated ketazine with F2Si(i-Pr)2 in a molar ratio of 1 : 2 [t-Bu(RH2C)C=N-N=C(CH2R’)t-Bu, 10: R = SiMe3, R’ = SiMe2Ph; 11: R,R’ = FSi(i-Pr)2]. The tris(ketazinyl)fluorosilane 12 is isolated from the reaction of SiF4 with the lithiated ketazine. 2-Alkenyl-1,2-diaza-3-sila-5-cyclopentenes, t-Bu(CH2)C- [N-SiR,R’-CH2-C(t-Bu)=N], (14 - 17) are obtained from the dilithiated ketazine and Hal2SiRR’. (14: Hal = Cl, R = Me, R’ = Ph; 15: Hal = F,R = t-Bu, R’ = Ph; 16: Hal = F,R = t-Bu, R’ = F; 17: Hal = F, R = N(t-Bu)SiMe3, R’ = F). X-ray structure analyses are presented for 7, 11, and 17.

From lithium ketazides to isomeric silylketazine-rings – imine-enamine tautomerism

“…Synthesis of a 1,2-diaza-3-sila-hepta-5,7-diene (7) and -5-pentene (8) The reaction of the dilithium salt 6 and t Bu 2 SiF 2 leads to the formation of the seven-membered diazasilacycloheptadiene (7), which contains endocyclicly one imine and one enamine unit. The following reaction mechanism is possible (Scheme 4).…”

“…In order to prepare comparable four-, five-, and sevenmembered ring isomers, we carried out the reaction of a dilithiated Me 3 Si-substituted ketazine [7] with t Bu 2 SiF 2 and could isolate only the five-membered ring 8, …”

“…1 3 ) 2 ), 29.3 (C(CH 3 ) 3 ), 30.5 (C(CH 3 ) 3 , 1 J 13 C 13 C ¼ 35:6 Hz), 38.5 (C(CH 3 ) 3 , 1 J 13 C 13 C ¼ 41:2 Hz, 1 J 13 C 13 C ¼ 35:6 Hz), 39, 0 (C(CH 3 ) 3 , 1 J 13 C 13 C ¼ 49:7 Hz), 116.6 (@CH, 1 J 13 C 13 C ¼ 74:5 Hz, 1 J 13 C 13 C ¼ 52:4 Hz), 153, 2 (C@C, 1 J 13 C 13 C ¼ 74:5 Hz, 1 J 13 C 13 C ¼ 41:2 Hz, 1 J 13 C 13 C ¼ 38:6 Hz), 160, 6 (C@N, 1 J 13 C 13 C ¼ 52:4 Hz, 1 J 13 C 13 C ¼ 49:7 Hz). 15 To a solution of 0.1 mol (26.8 g) of the silyl substituted ketazine, t BuMeC@N-N@C( t Bu)CH 2 SiMe 3 [7] in 250 ml n-hexane were added 0.2 mol (12.8 g) n-BuLi (15%) in n-hexane. The mixture was heated to reflux for 3 h, then cooled to room temperature and added drop wise to 0.1 mol (18.0 g) t Bu 2 SiF 2 in 50 ml THF.…”

“…Recently represented reactions of lithiated ketazines with haloboranes [5,6], -silanes [7,8], and -phosphanes [6] yielded surprising results, e.g., the backbone of the ketimine structure is maintained in reactions with halotriorganylsilanes [7,8]. On the other hand, half an imine-enamine isomerization occurs in reactions with dihaloboranes, -silanes, and -phosphanes [4,8].…”

Microwave Assisted Green Synthesis of Pyrazole, 1, 2, 3‐ Triazole Based Novel Benzohydrazones and Their Antibacterial Activities

“…The hydrazones constitute an important class of biologically active molecules, which have attracted attention of medicinal chemists due to their wide ranging pharmacological properties. They act as intermediate for synthesis of various heterocyclic compounds such as 1, 3, 4‐oxadiazolines, 1, 3, 4‐oxadiazines, 1, 2, 4‐triazines, pyrazoles , and 1, 3, 4‐oxadiazolines, azetidinones, thiazolidinones . They are reported to show wide variety of biological properties such as anti‐convulsant , anti‐HIV, anticancer , antitubercular , antioxidant , antimicrobial , and antimalarial activity .…”